🍯 Do the heaviest liquids always sink to the bottom?

My hypothesis

If I change which kitchen liquid is in the cup, then how many grams a quarter cup of it weighs will ______, because ______.

🔊 You fill in the blanks. Think about what it means when one cup of something weighs more than the same cup of something else. A guess is a good because: the test finds out.

Change, measure, keep the same

Scientists call the thing you change the independent variable and the thing you measure the dependent variable. The things you keep the same are the controls: if one of them changed too, you wouldn't know which change made the difference. Try each of the 6 levels 3 times.

What you need

• 🍯 Honey
• 🫙 Corn syrup
• 🫧 Dish soap
• 🥛 Milk
• 🚰 Water from the tap
• 🛢️ Cooking oil
• 🌈 Food colouring: 1 drop, for the water
• ⚖️ A kitchen scale
• 🥛 A measuring cup
• 🫙 A clear jar or tall glass: a tall clear glass
• 🥄 A spoon
• 🧽 A sponge or cloth, for wiping up

Steps

1. Put the empty measuring cup on the kitchen scale and press zero.🔊
2. Fill it to the quarter-cup line with honey, and write down the grams.🔊
3. Scrape the honey back into its jar, rinse and dry the cup, and weigh a quarter cup two more times.🔊
4. Weigh corn syrup, dish soap, milk, water and oil the same way, three times each.🔊
5. Find the mean for each liquid, and put them in order, heaviest first.🔊
6. Stir one drop of food colouring into the water, so it shows in the tower.🔊
7. Pour a little of the heaviest liquid into the middle of a tall clear glass.🔊
8. Pour each next liquid slowly down the back of a spoon, in your heaviest-first order.🔊
9. Do the layers stack in the same order as your grams? Draw the tower and label it.🔊
10. Draw a bar graph of the mean grams for each liquid.🔊
11. The tower isn't for drinking: pour it away when you're done.🔊

Every step is one you can do yourself, with a grown-up nearby. Write each number down straight away, in the table below, so nothing is lost.

Your results table

From 4th grade, add the tries for each level and divide by how many there were: that's the mean, and it goes in the last column. Then draw a bar graph, one bar for each thing you tried.

Why it works

🔊 Density is how much stuff is packed into a space, so a quarter cup of honey weighs more than a quarter cup of water. Poured gently, denser liquids sink below less dense ones, so the layers stack in the order of their weights. Close pairs, like milk and dish soap, can swap places from brand to brand, and liquids that mix, like milk and water, slowly blend where they meet.

Going further (7th and up): Change a second thing: weigh each liquid cold from the fridge too, and draw cold and room-temperature bars side by side.

Board layout

This project at your grade

Every grade this project fits works out a mean. See every project for 4th grade, or print a blank results table.

What a judge will ask

• What did you change, and what did you measure? I changed which kitchen liquid is in the cup and measured how many grams a quarter cup of it weighs, in grams.
• What did you keep the same, and why does that matter? I kept the same quarter-cup measure, filled to the line and the same kitchen scale, set to zero with the empty cup on it the same, so the only difference was which kitchen liquid is in the cup.
• How many times did you test it? 3 times at each of my 6 levels.
• If you did it again, what would you change or test next? I'd weigh each liquid cold from the fridge too, and draw cold and room-temperature bars side by side.

Make it yours

Keep this project on this device and Peabody counts down to your fair day, with a plan for each day. Nothing is sent anywhere.

Try next

• 🥚 How much salt does it take to float an egg?3rd–7th grade · 1 day of testing · free🧪 Water, ice and mixing · 🧂 Kitchen things
• 🫧 Does dish soap stop oil and water from separating?3rd–8th grade · 1 day of testing · free🧪 Water, ice and mixing · 🧂 Kitchen things