Conducting the Experiment
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Watch this tutorial where we show you the steps!
PREPARATION
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Cut an orange into 8 pieces with your knife (ask an adult to help for this step). Repeat for the second orange.
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Squeeze 100 mL of juice into the beaker. Use the numbers on the side to tell you when to stop
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Pour the orange juice through a strainer into another beaker
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Pour 60mL of orange juice from the beaker into the measuring cylinder. Pour this into the first plastic cup
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Measure out 30mL of orange juice with the measuring cylinder. Pour this into the second plastic cup.
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Measure out 10mL of orange juice with the measuring cylinder. Pour this into the third plastic cup.
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Measure out 30mL of water using the measuring cylinder. Pour this into the second cup (the cup from step 5).
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Measure out 50ml of water using the measuring cylinder. Pour this into the third cup (the cup from step 6).
WEIGHING
9. Place one of the empty beakers on the weighing scale
10. Press the “tare” button. You will notice that the number on the scale is now 0. (Watch the weighing part of the video if you are unsure of this step)
11. Pour the first solution from the plastic cup to the beaker, record its weight in the first column of the table provided in the worksheet, and pour it back into the plastic cup.
12. Repeat step 10 and 11 for the other two solutions. They should all weigh around 60 grams.
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A CHEMICAL REACTION!
13. Using your teaspoon, scoop out 1 teaspoon of baking soda, making sure that the powder is flat on top of the spoon.
14. Pour it into the first cup and start the first timer for 1 minute.
15. Repeat steps 13 and 14 for the second and third cup
16. Observe the solutions for 1 minute. Which mixture produces the most bubbles?
17. After a minute, the bubbles should have stopped forming. Place an empty beaker on the weighing scale and press “tare” again.
18. Pour each liquid into the beaker one at a time, and record the weights in the second column of the table. You will notice that they weigh less than before.
19. Subtract the final weight of the solutions from their weight before adding the baking soda and record this in the third column of the table. This is how much gas (bubbles) was produced.
BE CAREFUL!
Every experiment has risks - things you need to watch out for. When conducting this experiment, make sure you:
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Wear gloves and goggles so that orange juice doesn't get in your eye. It hurts!
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We'll protect you!
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Be careful with the glass beakers and measuring cylinder. Broken glass can be very dangerous because you can cut yourself on it. Make sure to be gentle while using glass equipment!
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Ask an adult to help you when using the knife. Knives are sharp and could hurt you!
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OUCH!
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Watch this safety video for more information!
RECORDING YOUR RESULTS
Watch this video tutorial on how to record your results in the worksheet.
Here's a hint.....
What happened and why?
A chemical reaction!
From this website, you have learnt that a chemical reaction is what happens when one substance collides with another and makes a third substance.
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All chemical reactions have reactants. These are the substances that collide to produce the third substance. The third substance is called a product.
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Orange juice contains citric acid. This is the first reactant. Baking soda contains a substance called carbonate. This is the second reactant. When you mixed the baking soda with the orange juice, the acid and carbonate collided. When acids and carbonates collide, they react and produce gas, salt, and water. You couldn't see the water and salt in the cups but you saw bubbles. those bubbles were gas!
Why did the three cups have different amounts of bubbles?
From this website, you have also learnt that the rate of reaction is the speed that a reaction happens at. One of the factors that affect the rate of reaction is concentration.
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This experiment changed the concentration of the orange juice by mixing different amounts of orange juice and water. This affected the amount of citric acid in the solutions.
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In the first cup, there was just orange juice, so it had the most citric acid. The second cup had half orange juice and half water, so there was only half the amount of citric acid. The third cup had even less citric acid because most of the solution was water.
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The citric acid in the orange juice reacted with carbonate in the baking soda to produce the gas bubbles you saw. However, if there was less citric acid in the solution then it is less likely that the citric acid will collide with the carbonate, causing a reaction. This slows down the rate of reaction because the citric acid and the carbonate will take longer to collide. When the substances take longer to collide, they take longer to react and produce gas. This is why the cup with the most orange juice produced the most bubbles in one minute.
Click here to find out more!
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Citric acid
Carbonate
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gas, water, and salt
WHAT'S NEXT?
Now that you've completed this experiment, its time to try designing one yourself!