What it shows
Soaked seeds wake up, absorb water and start to grow roots and shoots. Measuring weight and sprout length every day shows how quickly the seed changes, and why sprouts are a popular food.
The science
A dry seed holds a tiny plant (embryo) and stored food. When soaked, it takes in water, swells, and enzymes begin to turn stored starch into sugars that feed the embryo. The root pushes out first, followed by the shoot. The weight rises mainly because of the water taken in.
Materials
Cost: under Rs 50. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- A handful each of whole moong and chana
- Two steel bowls or glass jars
- A thin cotton cloth
- A kitchen scale
- A ruler
- Water and a notebook
Safety
For this project: Wash hands before and after handling. Rinse sprouts well and an adult must decide if they are fit to eat; never eat sprouts that smell bad or look slimy.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Weigh 50 g of dry moong and 50 g of dry chana separately and write the weights.
Soak each in a bowl of water for 8 hours, then drain and weigh again.
Place each lot in a damp cloth or in a jar covered with muslin and keep in a warm, shaded spot.
Rinse with clean water twice a day and drain well so they do not rot.
Every day weigh the seeds and measure the length of the longest five sprouts.
Record the numbers in a table for five days.
Plot a line graph of average sprout length against day for both seeds.
Compare which seed grew faster and which gained more weight.
What you should see
Both seeds gain weight after soaking and sprouts lengthen day by day. Moong usually sprouts faster than chana, and the graph shows this clearly.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1What do seeds need to sprout?
Water, air and a suitable warmth.
2Why does weight jump after soaking?
The seed absorbs water.
3Which part comes out first?
The root, called the radicle.
4Why rinse twice a day?
To keep them moist and stop moulds growing.
Take it further
Grow sprouts in light and in a dark cupboard and compare their colour and length.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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